Map drawing device

ABSTRACT

A map drawing device includes a drawing parameter DB  7  for storing drawing parameter data which define specifications of map drawing, a drawing parameter managing unit  1  for managing the descriptions of the drawing parameter data, a map drawing unit  9  for carrying out map drawing according to the descriptions of the drawing parameter data managed by the drawing parameter managing unit  1,  and a map drawing control unit  8  for controlling the map drawing carried out by the map drawing unit  9  according to the descriptions of the drawing parameter data managed by the drawing parameter managing unit  1.

FIELD OF THE INVENTION

The present invention relates to a map drawing device that draws a map.

BACKGROUND OF THE INVENTION

In a conventional map drawing device, drawing parameters, such asinformation about a drawing procedure for drawing a map and whether ornot each item to be drawn can be displayed according to drawingconditions, a drawing parameter specific to each item to be drawn, andparameters of a graphic system, are held fixedly in a drawing processingprogram (for example, refer to patent reference 1).

-   [Patent reference 1] JP, 2003-263645,A

Conventionally, drawing parameters are held fixedly in a drawingprocessing program, as mentioned above. More specifically, drawingparameters are described directly in a drawing processing program.Therefore, after a drawing processing program is compiled and is mountedin a drawing device, the descriptions of the drawing parametersdescribed in the drawing processing program cannot be changed. A problemis therefore that when the descriptions of the drawing parameters haveto be changed according to change in the drawing specifications, amodification of replacing the drawing processing program with a drawingprocessing program in which drawing parameters complying with thechanged drawing specifications are described has to be made.

The present invention is made in order to solve the above-mentionedproblem, and it is therefore an object of the present invention toprovide a map drawing device that can flexibly adapt to change in thedrawing specifications thereof.

DISCLOSURE OF THE INVENTION

In accordance with the present invention, there is provided a mapdrawing device including: a drawing parameter database for storingdrawing parameter data for defining specifications of map drawing; adrawing parameter managing unit for managing descriptions of the drawingparameter data read from the drawing parameter database; a map drawingunit for carrying out map drawing according to the descriptions of thedrawing parameter data managed by the drawing parameter managing unit;and a map drawing control unit for controlling the map drawing carriedout by the map drawing unit according to the descriptions of the drawingparameter data managed by the drawing parameter managing unit.Therefore, the map drawing device in accordance with the presentinvention has an advantage of being able to flexibly adapt to any changein the drawing specifications.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram showing the structure of a map drawing devicein accordance with Embodiment 1 of the present invention;

FIG. 2 is a view showing an example of a drawing layer structure;

FIG. 3 is a flow chart showing a flow of a drawing parameterinitialization process carried out by the map drawing device show inFIG. 1;

FIG. 4 is a view showing the data structure of data managed by a displaydetermination managing unit shown in FIG. 1;

FIG. 5 is a view showing the data structure of data managed by a drawingorder managing unit shown in FIG. 1;

FIG. 6 is a flow chart showing a flow of a map drawing process carriedout by the map drawing device shown in FIG. 1; and

FIG. 7 is a view showing an example of a setting of a drawing command.

PREFERRED EMBODIMENTS OF THE INVENTION

Hereafter, in order to explain this invention in greater detail, thepreferred embodiments of the present invention will be described withreference to the accompanying drawings. Embodiment 1.

FIG. 1 is a block diagram showing the structure of a map drawing devicein accordance with Embodiment 1 of the present invention. In FIG. 1, thedrawing parameter managing unit 1 includes a drawing scenario managingunit 2, an individual drawing parameter managing unit 3, a graphicsparameter managing unit 4, a graphics resource managing unit 5 and aparameter initializing unit 6, and manages drawing parameters used formap drawing. The above-mentioned drawing parameters define the drawingspecifications of the map drawing device in accordance with Embodiment1, and are roughly divided into the following four types of drawingparameters: a drawing scenario parameter, an individual drawingparameter, a graphics parameter, and a graphics resource parameter.

In this Embodiment 1, a case in which the drawing parameters are writtenin XML (eXtensible Markup Language) will be mentioned as an example. Thedrawing parameters in accordance with the present invention can bealternatively described as binary data or can be alternatively describedin a specific format as long as the drawing parameters have only to bedescribed in a data format which can be read and written by the drawingparameter managing unit 1, the map drawing control unit 8, and the mapdrawing unit 9.

The drawing scenario managing unit 2 has a display determinationmanaging unit 12 and a drawing order managing unit 13, and manages thedata descriptions of the above-mentioned drawing scenario parameter.Data for controlling whether each of items to be drawn can be displayedaccording to both drawing conditions and a drawing order are set to thedrawing scenario parameter. Icons and so on, as well as elementsdisplayed on a map, are included in the items to be drawn.

The display determination managing unit 12 manages data, which isincluded in the data set to the above-mentioned drawing scenarioparameter, for controlling whether each of items to be drawn can bedisplayed according to the drawing conditions. The drawing conditionsinclude, for example, a map display mode (a north reference displaymode, a vehicle direction display mode, or the like), a display screenscroll speed, a season, a time, and so on. An example of thedescriptions of the drawing scenario parameter data which defines suchthe drawing conditions is shown below.

<drawing scenario>  <display condition>  <item to be drawn=“item to bedrawn name”>   <drawing condition=“condition 1” value=“1”/>   <drawingcondition=“condition 2” value=“0”/>   <drawing condition=“condition 3”value=“1”/>   <drawing condition=“condition 4” value=“1”/>   <drawingcondition=“condition 5” value=“1”/>   ...  </item to be drawn>  ... </display condition> </drawing scenario>

The drawing order managing unit 13 manages data, which is included inthe data set to the above-mentioned drawing scenario parameter, forcontrolling whether each of the items to be drawn can be displayedaccording to the drawing order.

As shown in FIG. 2, a case in which drawing is performed for each of aplurality of drawing layers by a graphics system will be mentioned as anexample. In this case, specification of a layer in which each of theitems to be drawn is to be drawn is equivalent to the specification ofwhether or not each of the items to be drawn can be drawn according tothe drawing order. Furthermore, a drawing priority (priority) given toeach of the items to be drawn in each identical drawing layer can alsobe set to the above-mentioned drawing scenario parameter. Hereafter, anexample of the descriptions of the drawing scenario parameter data whichdefines the drawing order of the items to be drawn will be shown.

<drawing scenario>  <drawing order>  <item to be drawn=“item to be drawnname” drawing layer=“1” priority=“1”/>  ...  </drawing order> </drawingscenario>

The individual drawing parameter managing unit 3 manages the datadescriptions set to the above-mentioned individual drawing parameter.Data which defines a drawing process specific to each of the items to bedrawn is set to the above-mentioned individual drawing parameter. In acase in which, for example, a road line is drawn as an item to be drawn,a line thickness provided for each map scale, a color, a value of a flagshowing whether or not a border is to be drawn, and so on are set to theindividual drawing parameter of the item to be drawn. Furthermore, in acase in which a map icon is drawn as an item to be drawn, a scaleaccording to the position of the map icon, a font and a color ofcharacters, and so on are set to the individual drawing parameter of theitem to be drawn. In the data set to the above-mentioned individualdrawing parameter, different descriptions are described for each of theitems to be drawn (map items). Although data about a pen and a brushwhich are used at the time of drawing each of the items to be drawn canbe described in the above-mentioned individual drawing parameter, thedata descriptions about such a pen and a brush are managed by a penbrush pattern managing unit 14 which will be mentioned below. Hereafter,an example of the descriptions of the individual drawing parameter datain a case of drawing a road line as an item to be drawn will be shown.

<individual drawing parameter>  <road line>  <line parameter>   <mapscale=“25m” line thickness=“10” border=“2” color RGB=“0,0,255”/>   <mapscale=“50m” line thickness=“8” border=“2” color RGB=“0,0,255”/>   <mapscale=“100m” line thickness=“5” border=“1” color RGB=“0,0,255”/>   <mapscale=“1K” line thickness=“2” border=“1” color RGB=“0,0,255”/>   <mapscale=“5K” line thickness=“2” border=“0” color RGB=“0,0,255”/>   <mapscale=“10K” line thickness=“2” border=“0” color RGB=“0,0,255”/>   <mapscale=“20K” line thickness=“1” border=“0” color RGB=“0,0,255”/>   <mapscale=“50K” line thickness=“1” border=“0” color RGB=“0,0,255”/>   <mapscale=“100K” line thickness=“1” border=“0” color RGB=“0,0,255”/>   ... </line parameter>  </road line> </individual drawing parameter>

The graphics parameter managing unit 4 has a pen brush pattern managingunit 14 and a font managing unit 15, and manages the data descriptionsof the above-mentioned graphics parameter. Data about graphics tools anda character font which are used for the map drawing are described in thegraphics parameter. The graphics parameter data include, for example,data about graphics tools, such as a pen and a brush, which areconstantly registered in the graphics system, and data about a characterfont (a system font) and so on which are handled by the graphics system.

The graphics system is a component of the map drawing unit 9, andperforms a drawing process according to the data descriptions of thegraphics parameter. Furthermore, the graphics system is configured ofboth hardware for drawing 2D or 3D graphics which is included in acomputer which functions as the map drawing device in accordance withthe present invention, and a software library which is included insoftware performed by the computer.

The pen brush pattern managing unit 14 manages the descriptions of dataabout a pen, a brush and a pattern, which is included in the data set tothe graphics parameter. The data about a pen, a brush and a patternspecifies graphics tools (a pen and a brush) used in the drawing processcarried out by the graphics system, and the drawing specifications ofthe graphics tools. For example, on the basis of the data about a pen, abrush and a pattern, the types of a pen and a brush used, the thicknessof a line drawn with the pen, and a color and a pattern with which arectangular region is filled in are set. Furthermore, the font managingunit 15 manages the descriptions of data about a font, which is includedin the data set to the above-mentioned graphics parameter. In the dataabout a font, a font (a system font) required for character drawing bythe graphics system and font replacement information are described.Hereafter, an example of the descriptions of the graphics parameter datawill be shown.

<graphics parameter>  <system pen>  <pen type=“Solid” line thickness=“2”color RGB=“0, 0, 0”/>  ...  </system pen>  <system brush>  <brushtype=“Pattern” Texture=“System/aaa.bmp”/>  ...  </system brush>  <font> <system font=“A gothic”/>  <font replacement>   <font name=“mediumgothic” font to be replaced=“A gothic”/>   ...  </font replacement> </font> </graphics parameter>

The graphics resource managing unit 5 is provided with an icon managingunit 16 and a texture managing unit 17, and manages the datadescriptions of the graphics resource parameter. In this graphicsresource parameter, data which defines graphics resources used in themap drawing is described. The graphics resources include, for example,icons which are displayed in the drawing results and texture imageswhich are used at a time of 3D map drawing.

The icon managing unit 16 manages the descriptions of data about theicons, which is included in the graphics resource parameter. The texturemanaging unit 17 manages the descriptions of data about the textureimages, which is included in the graphics resource parameter. Hereafter,an example of the descriptions of the graphics resource data will beshown.

<graphics resource>  <symbol>  <symbol    name=“parking    lot   mark”   icon data=“System/icon/parking.bmp”/>  <symbol   name=“entrance   inhibition   mark”  icondata=“System/icon/stop.bmp”/>  ...  </symbol>  <texture>  <model  name=“general   building”  texture   data=“System/Texture/building1.bmp/>  <model name=“tree” texturedata=“System/Texture/Tree.bmp/>  ...  </texture> </graphics resource>

In an initialization process of initializing the drawing parameter datamanaged by the drawing parameter managing unit 1, the parameterinitializing unit 6 reads the drawing parameter data from the drawingparameter database 7, and sets the initial values of the correspondingdrawing parameter data to each of the managing units which configure thedrawing parameter managing unit 1. The drawing parameter database(referred to as the drawing parameter DB from here on) 7 is the one inwhich the drawing parameter data managed by the drawing parametermanaging unit 1 are described. In this case, the drawing parameter dataare described in a data form as shown in the above-mentioned example ofdescriptions in the drawing parameter DB 7.

The map drawing control unit 8 controls the map drawing process carriedout by the map drawing unit 9 on the basis of the drawing scenarioparameter data inputted thereto from the drawing scenario managing unit2 of the drawing parameter managing unit 1. Under control of the mapdrawing control unit 8 on the basis of the drawing scenario parameterdata, the map drawing unit 9 performs the map drawing using map dataaccording to the drawing parameter data set up by the individual drawingparameter managing unit 3, the graphics parameter managing unit 4 andthe graphics resource managing unit 5.

The map data acquiring unit 10 reads map data from the map database 11according to a request from the map drawing unit 9, and sets the mapdata to the map drawing unit 9. The map database (referred to as the mapDB from here on) 11 is the one in which the above-mentioned map data aredescribed. The map data show a map of a predetermined area, and objectson the map.

By loading a drawing processing program in accordance with the scope ofthe present invention into a computer, and then controlling theoperation of the drawing processing program, the above-mentioned drawingparameter managing unit 1, the above-mentioned map drawing control unit8, the above-mentioned map drawing unit 9 and the above-mentioned mapdata acquiring unit 10 can be implemented as a concrete means in whichsoftware and hardware run on the computer in cooperation with eachother. Furthermore, the drawing parameter DB 7 and the map DB 11 areconfigured in a storage unit from and into which each of the drawingparameter managing unit 1 and the map data acquiring unit 10 can readand write data.

Next, the operation of the map drawing device will be explained.

FIG. 3 is a flow chart showing a flow of the drawing parameterinitialization process carried out by the map drawing device shown inFIG. 1, and the details of the process will be explained with referenceto this chart and FIG. 1.

The parameter initializing unit 6 of the drawing parameter managing unit1 reads the drawing parameter data from the drawing parameter DB 7 (stepST1), and analyzes the drawing parameter data acquired thereby (stepST2). For example, the parameter initializing unit analyzes the tagcontents (the contents described within < >) of the drawing parameterdata written in XML to determine the types of the drawing parameters.

The parameter initializing unit 6 then sets the drawing parameter datato the drawing scenario managing unit 2, the individual drawingparameter managing unit 3, the graphics parameter managing unit 4, andthe graphics resource managing unit 5 according to the types of thedrawing parameter data (step ST3).

After the drawing scenario parameter data are set to the drawingscenario managing unit 2 by the parameter initializing unit 6, thedrawing scenario managing unit 2 outputs the data about a drawing layersetting (a setting of the drawing order), which is included in thisdrawing scenario parameter data, to the map drawing control unit 8. Themap drawing control unit 8 sets information about drawing layers foreach of which map drawing is to be performed to the map drawing unit 9on the basis of the descriptions of the inputted data about a drawinglayer setting (step ST4).

The graphics resource managing unit 5 also sets the data descriptions ofthe graphics resource parameter inputted thereto from the parameterinitializing unit 6 to the map drawing unit 9 (step ST5). As a result,the map drawing unit 9 registers the graphics resources specified by thegraphics resource parameter data into the graphics system.

Hereafter, the details of drawing parameter management carried out byeach of the managing units 2 to 5 of the drawing parameter managing unit1 will be explained.

(1) Drawing Parameter Management Carried Out by the DisplayDetermination Managing Unit 12

FIG. 4 is a view showing the data structure of data managed by thedisplay determination managing unit shown in FIG. 1. Condition bitsshown in FIG. 4 are digital data which defines the drawing conditions,and one bit of these condition bits is defined as a bit showing whetheror not an item to be drawn can be displayed. Thus, in the data managedby the display determination managing unit 12, a bit showing whether ornot an item to be drawn can be displayed is assigned to each of thedrawing conditions which are assumed in advance. In case in which theitem to be drawn is displayed, a digital value of 1 is set to this bit,whereas in case in which the item to be drawn is not displayed, adigital value of 0 is set to the bit.

Furthermore, the drawing condition data including bits each showingwhether or not an item to be drawn can be displayed are expressed as,for example, a 32-bit integer type array, and the bits each fordetermination of whether or not an item to be drawn can be displayed areset to all the items to be drawn respectively. When the map drawing unit9 carries out the map drawing process, the display determinationmanaging unit 12 receives an inquiry about whether or not each of theitems to be drawn can be displayed from the map drawing unit 9 via themap drawing control unit 8, and, in response to this inquiry, determineswhether or not each of the items to be drawn can be displayed on thebasis of the drawing scenario parameter data which the displaydetermination managing unit itself manages.

(2) Drawing Parameter Management Carried Out by the Drawing OrderManaging Unit 13

By using the data about the drawing order, which is included in thedrawing scenario parameter data, the drawing order managing unit 13generates management data for controlling whether or not each of theitems to be drawn can be displayed according to the drawing order. FIG.5 is a view showing the data structure of the data managed by thedrawing order managing unit shown in FIG. 1. As shown in FIG. 5, thedrawing order managing unit 13 generates table data in which items to bedrawn which are to be assigned to each drawing layer are registeredaccording to the data about the drawing order (refer to a left-hand sideof the view shown in FIG. 5).

The drawing order managing unit 13 then generates table data in which alayer ID for identifying an assigned drawing layer and an intra-layerpriority showing a drawing priority within the drawing layer are broughtinto correspondence with each of the items to be drawn (refer to aright-hand side of the view shown in FIG. 5). The drawing order managingunit 13 manages the drawing order of the items to be drawn withreference to this table data. The drawing order managing unit 13 alsosets the data descriptions of the above-mentioned table to the mapdrawing control unit 8. The map drawing control unit 8 controls the mapdrawing carried out by the map drawing unit 9 according to the datadescriptions of the above-mentioned table.

(3) Drawing Parameter Management Carried Out by the Individual DrawingParameter Managing Unit 3

When the individual drawing parameter data about each of the items to bedrawn is set to the individual drawing parameter managing unit 3 fromthe parameter initializing unit 6, the individual drawing parametermanaging unit 3 generates management data in which an individual drawingparameter is brought into correspondence with each of the items to bedrawn. As this management data, for example, table data in which each ofthe items to be drawn is brought into correspondence with its individualdrawing parameter can be considered.

(4) Drawing Parameter Management Carried Out by the Graphics ParameterManaging Unit 4

The pen brush pattern managing unit 14 of the graphics parametermanaging unit 4 extracts the data about a pen, a brush and a patternfrom the graphics parameter data inputted thereto from the parameterinitializing unit 6. The pen brush pattern managing unit 14 thenregisters the data about a pen, a brush and a pattern into the graphicssystem, and also manages the ID of this data.

Furthermore, the font managing unit 15 extracts the data about a systemfont from the above-mentioned graphics parameter data. After that, thefont managing unit 15 registers the data about a system font into thegraphics system, and manages the ID of this data.

(5) Drawing Parameter Management Carried Out by the Graphics ResourceManaging Unit 5

The icon managing unit 16 of the graphics resource managing unit 5extracts the data about icons from the graphics resource parameter datainputted thereto from the parameter initializing unit 6, and registersthe data into the graphics system. After that, the icon managing unit 16manages the data as array data in which an icon ID for identifying eachicon registered into the graphics system is brought into correspondencewith the item-to-be-drawn ID of an item to be drawn corresponding tothis icon.

Furthermore, the texture managing unit 17 extracts the data abouttexture images from the above-mentioned graphics resource parameterdata, and registers the data into the graphics system. After that, thetexture managing unit 17 manages the data as array data in which atexture ID for identifying each texture image registered into thegraphics system is brought into correspondence with the item-to-be-drawnID of an item to be drawn corresponding to this texture image.

Next, the map drawing process will be explained.

FIG. 6 is a flow chart showing a flow of the map drawing process carriedout by the map drawing device shown in FIG. 1, and the details of theprocess will be explained with reference to this chart and FIG. 1.

The map drawing control unit 8 commands the map drawing unit 9 to carryout the drawing process according to the data descriptions of thedrawing scenario parameter set thereto from the drawing scenariomanaging unit 2 (step ST1 a). At this time, the map drawing control unit8 sets a map graphic scale, a map display mode (a north referencedisplay mode, a vehicle direction display mode, or the like), etc. tothe map drawing unit 9. The map drawing control unit 8 can alternativelyset information about a map graphic scale, a map display mode, etc. tothe map drawing unit 9 according to a user command which is inputted tothe map drawing device via an input unit.

Furthermore, the map drawing unit 9 makes a request of the map dataacquiring unit 10 for map data about a map of an area required for themap drawing. The map data acquiring unit 10 reads map data according tothis request from the map DB 11 and outputs the map data to the mapdrawing unit 9. As a result, the map drawing unit 9 acquires the mapdata about the map of the area required for the map drawing (step ST2a).

After acquiring the map data, the map drawing unit 9 inquires of the mapdrawing control unit 8 about the current drawing mode (the drawingconditions) to check the current drawing mode (step ST3 a). Next, themap drawing control unit 8 inquires of the display determinationmanaging unit 12 whether the map drawing control unit should display anitem to be drawn in the current drawing mode. The display determinationmanaging unit 12 determines whether the map drawing control unit shoulddisplay the item to be drawn which is the target for the determinationin response to this inquiry (step ST4 a). As a criterion for thedetermination, for example, the determination bits as shown in FIG. 4can be considered.

When the display determination managing unit 12 determines that it doesnot display the item to be drawn which is the target for thedetermination in the current drawing mode, the display determinationmanaging unit 12 returns to the process of step ST4 a and makes atransition to a waiting state in which the display determinationmanaging unit is waiting for an inquiry about an item to be drawn whichis the next target for the determination.

In contrast, when the determination result shows that the item to bedrawn which is the target for the determination is displayed, thedisplay determination managing unit 12 notifies the ID of the item to bedrawn which is the target for the determination to the individualdrawing parameter managing unit 3. The individual drawing parametermanaging unit 3 sets the individual drawing parameter data correspondingto the item-to-be-drawn ID notified thereto from the displaydetermination managing unit 12 to the map drawing unit 9. As a result,the map drawing unit 9 acquires the individual drawing parameter datacorresponding to the item to be drawn which is the target for thedetermination (step ST5 a).

At this time, when determining that the item to be drawn which is thetarget for the determination is an icon from the data descriptions ofthe individual drawing parameter of the item to be drawn, the individualdrawing parameter managing unit 3 notifies the ID of the item to bedrawn to the graphics resource managing unit 5. The icon managing unit16 of the graphics resource managing unit 5 searches for the icon IDcorresponding to the ID of the item to be drawn notified thereto fromthe individual drawing parameter managing unit 3, and sets the icon IDwhich is the search result to the map drawing unit 9.

Also when determining that the item to be drawn which is the target forthe determination is a texture image from the data descriptions of theindividual drawing parameter of the item to be drawn, the individualdrawing parameter managing unit 3 notifies the ID of the item to bedrawn to the graphics resource managing unit 5. The icon managing unit16 of the graphics resource managing unit 5 searches for the texture IDcorresponding to the ID of the item to be drawn notified thereto fromthe individual drawing parameter managing unit 3, and sets the textureID which is the search result to the map drawing unit 9.

Furthermore, when determining that an pen and a brush are specified fordrawing the above-mentioned item to be drawn which is the target for thedetermination from the data descriptions of the individual drawingparameter of the item to be drawn, the individual drawing parametermanaging unit 3 notifies the data about the pen and the brush to thegraphics parameter managing unit 4. The pen brush pattern managing unit14 of the graphics parameter managing unit 4 sets the pen and the brushcorresponding to the data notified thereto from the individual drawingparameter managing unit 3 to the map drawing unit 9.

Furthermore, when a system font is specified by the data descriptions ofthe individual drawing parameter of the item to be drawn which is thetarget for the determination, the individual drawing parameter managingunit 3 notifies the data about the system font to the graphics parametermanaging unit 4. The font managing unit 15 of the graphics parametermanaging unit 4 sets the data about the font corresponding to the datanotified thereto from the individual drawing parameter managing unit 3to the map drawing unit 9. The above-mentioned process corresponds tostep ST6 a.

After up to the process in step ST6 a is completed, the map drawingcontrol unit 8 specifies a drawing layer in which the item to be drawnwhich is the target for determination is to be drawn on the basis of thedata about the drawing order set thereto from the drawing order managingunit 13 (refer to FIG. 5). After that, the map drawing control unit 8registers a drawing command for drawing the above-mentioned item to bedrawn in the above-mentioned drawing layer (step ST7 a).

Next, the map drawing control unit 8 determines whether it has performedthe processes in steps ST4 a to ST7 a on all the items to be drawn usedfor the map drawing (step ST8 a). When having not performed theprocesses in steps ST4 a to ST7 a on all the items to be drawn yet, themap drawing control unit 8 repeats the processes in steps ST4 a to ST7 auntil it has performed the processes on all the items to be drawn. Whenregistering drawing commands respectively corresponding to the drawinglayers in this processing loop, the map drawing control unit 8constructs a command list of commands 12-1, 12-2, . . . , 12-n in whichthe drawing commands are arranged in a line in order of the drawingpriorities of the items to be drawn as shown in FIG. 7. For example, themap drawing control unit 8 generates list data 12-1 to 12-n forrespectively storing the drawing commands arranged in the order of thedrawing priorities for the drawing layers by using the drawing layers,the items to be drawn and the table data about their drawing prioritiesas shown in FIG. 5. The map drawing control unit inserts the drawingcommand for drawing the item to he drawn which is the target fordetermination with the different types of drawing parameters set up inthe above-mentioned processing loop into the list of the correspondingdrawing priority of the above-mentioned list data.

When the map drawing control unit 8, in step ST8 a, determines that ithas performed the processes on all the items to be drawn, and havecompleted the registration of all the drawing commands, the map drawingcontrol unit 8 sets the generated drawing commands (the drawing commandlist) to the graphics system of the map drawing unit 9. The graphicssystem draws a map by executing the drawing commands set up by the mapdrawing control unit 8 in order of them arranged in the list (step ST9a). Thus, in the map drawing device in accordance with Embodiment 1, themap drawing unit 9 can carry out the map drawing by simply executing thedrawing commands arranged in the list in order of their drawingpriorities. Therefore, even if a change is made to the drawingspecifications, by generating a drawing command list complying with thechange in the drawing specifications without newly configuring a programlogic, the map drawing device in accordance with this Embodiment cancontrol whether or not to display each of items to be drawn and thedrawing order in which the items to be drawn are drawn according to thedrawing mode (the drawing conditions).

As mentioned above, the map drawing device in accordance with thisEmbodiment 1 includes the drawing parameter DB 7 for storing drawingparameter data which define the specifications of map drawing, thedrawing parameter managing unit 1 for managing the descriptions of thedrawing parameter data read from the drawing parameter DB 7, the mapdrawing unit 9 for performing the map drawing according to thedescriptions of the drawing parameter data managed by the drawingparameter managing unit 1, and the map drawing control unit 8 forcontrolling the map drawing performed by the map drawing unit 9according to the descriptions of the drawing parameter data managed bythe drawing parameter managing unit 1. Because the map drawing device inaccordance with this Embodiment 1 is configured in this way, the mapdrawing device in accordance with this Embodiment 1 can perform the mapdrawing by simply registering drawing parameters complying with thedesired drawing specifications into the drawing parameter DB 7 withoutproviding a drawing processing program in which the drawing parametersfor defining the drawing specifications are described (a drawingprocessing program for holding the drawing parameters fixedly).Therefore, the map drawing device in accordance with this Embodiment 1can adapt to any change in the drawing specifications without having tocarry out a modification of replacing the existing drawing processingprogram with a new drawing processing program, or the like.

INDUSTRIAL APPLICABILITY

As mentioned above, because the map drawing device in accordance withthe present invention can flexibly adapt to any change in the drawingspecifications, the map drawing device in accordance with the presentinvention is suitable for use as, for example, a map drawing devicemounted in a car navigation system for which a change in the drawingspecifications is assumed according to an update of maps.

1. A map drawing device comprising: a drawing parameter database forstoring drawing parameter data for defining specifications of mapdrawing; a drawing parameter managing unit for managing descriptions ofthe drawing parameter data read from said drawing parameter database; amap drawing unit for carrying out map drawing according to thedescriptions of the drawing parameter data managed by said drawingparameter managing unit; and a map drawing control unit for controllingthe map drawing carried out by said map drawing unit according to thedescriptions of the drawing parameter data managed by said drawingparameter managing unit.
 2. The map drawing device according to claim 1,characterized in that the drawing parameter managing unit includes: adrawing scenario managing unit for managing descriptions of drawingscenario parameter data, which is included in the drawing parameterdata, for controlling both whether or not an item to be drawn can bedisplayed according to drawing conditions, and whether or not an item tobe drawn can be displayed according to a drawing order; an individualdrawing parameter managing unit for managing descriptions of individualdrawing parameter data, which is included in the drawing parameter data,for defining a drawing process specific to each item to be drawn; agraphics parameter managing unit for managing descriptions of graphicparameter data, which is included in the drawing parameter data, fordefining a graphics tool and a character font which are used for the mapdrawing; a graphics resource managing unit for managing descriptions ofgraphics resource parameter data, which is included in the drawingparameter data, for defining a graphics resource used for the mapdrawing; and a parameter initializing unit for reading said drawingparameter data from the drawing parameter database when the map drawingdevice carries out a drawing process of drawing a map, and for settingcorresponding drawing parameter data to each of said managing units. 3.The map drawing device according to claim 2, characterized in that thedrawing scenario managing unit includes: a display determinationmanaging unit for managing descriptions of data, which is included inthe drawing scenario parameter data, for controlling whether or not anitem to be drawn can be displayed according to the drawing conditions;and a drawing order managing unit for managing descriptions of data,which is included in said drawing scenario parameter data, forcontrolling whether or not an item to be drawn can be displayedaccording to the drawing order.
 4. The map drawing device according toclaim 2, characterized in that the graphics parameter managing unitincludes: a pen brush pattern managing unit for managing descriptions ofdata about a graphic tool used for the map drawing, which is included inthe graphic parameter data; and a font managing unit for managingdescriptions of data about a font of characters to be drawn, which isincluded in said graphic parameter data.
 5. The map drawing deviceaccording to claim 2, characterized in that the graphics resourcemanaging unit includes: an icon managing unit for managing descriptionsof data about an icon which is included in the graphics resourceparameter data; and a texture managing unit for managing descriptions ofdata about texture data which is included in the graphics resourceparameter data.
 6. The map drawing device according to claim 2,characterized in that the map drawing control unit controls the mapdrawing carried out by the map drawing unit according to thedescriptions of the drawing scenario parameter data managed by thedrawing scenario managing unit, and said map drawing unit carries outthe map drawing according to the descriptions of the parameter datamanaged by the individual drawing parameter managing unit, the graphicsparameter managing unit, and the graphics resource managing unit.
 7. Themap drawing device according to claim 2, characterized in that the mapdrawing control unit generates a drawing command list including drawingcommands for drawing items to be drawn which are arranged in order ofdrawing priorities on a basis of the drawing scenario parameter datamanaged by the drawing scenario managing unit, and the map drawing unitcarries out the drawing by executing the drawing commands in saiddrawing command list one by one.